"It is vitally important for families to closely supervise children and instruct them to avoid any snakes, as well as playing in and around animal burrows, pipes and culverts where snakes may seek refuge," the department said in a statement.

The injured dog was treated at a veterinary hospital after being bitten Monday and has recovered, KNBC-TV reported. Its owner did not report the snake bite until late Tuesday, but he took a photo of the cobra before it vanished.

A cobra bite can kill a human within an hour.

It's illegal to keep cobras or other venomous snakes in Los Angeles. Authorities have not located the snake's owner.

The monocled cobra is native to South and Southeast Asia. An adult snake can grow to 4 to 7 feet long.